The present invention relates to a sensor light according to the precharacterizing clause of the main claim. Such apparatuses are generally known from the prior art and are marketed in large quantities in the form of external lights or garden lights which are controlled by an infrared motion sensor, for instance.
The principle of these lights which are used to form the generic type is that a light unit which is of virtually any desired esthetic configuration and has a lighting means is fastened to a support unit (base unit) which, on the one hand, ensures that the light unit is supplied with electrical power and, on the other hand, enables the sensor light to be mechanically fastened to the wall of a house or enables a fastening position of that kind. In addition, such lights contain a motion sensor system which, typically integrated in the support unit, provides a lens window for a motion sensor that is arranged behind it and is sensitive to infrared radiation.
The associated sensor electronics integrated in the support unit then make it possible for the light element to be switched on and off under the control of the sensor in response to a detected movement, suitable environmental or operating parameters additionally being able to be set or preselected, for instance the level of ambient brightness at which the apparatus is actually activated, a lighting time in the activated state (before the light unit is automatically deactivated again) or a detection range of the sensor system. These parameters are usually dictated by the location or environment, with the result that any installed sensor light must first of all be suitably set before correct starting.
However, the problem with the sensor lights known from the prior art is that these parameters can be set only in the installed state (that is to say on the wall of a house, for instance), with the result that awkward handling is often needed to access the setting elements provided on the sensor light or support unit and/or the sensor unit; it is necessary to use a ladder, for instance, when lights are hung high up. In addition, it is often difficult to correctly set the brightness or dusk threshold value for activation of the light; this is then often carried out in respective semi-darkness (respectively associated with the disadvantage that the setting elements are accordingly difficult to detect).
Another disadvantage of the apparatuses known from the prior art is that the detection range is extremely inhomogeneous in the circumferential direction, in particular in the case of wide detection angles and the use of a mirror for interacting with an infrared motion sensor; this is due to the fact that, with typically two sensor individual elements of a motion sensor, certain optical irradiation conditions result in the sensor's image being projected onto the sensor setting elements in different ways depending on the circumferential position of a person moving relative to the sensor.
However, since the motion detection signal is based on a difference between the individual signals which are respectively output by the elements, positions exist in the circumferential direction in which both sensor individual elements equally receive infrared images and a usable sensor differential signal is thus not produced, that is to say the motion sensor therefore exhibits a sensitivity range and thus detection range which are extremely inhomogeneous in the environmental direction.